Suggested so far:
– St. Catherine of Genoa. The Life and Doctrine of Saint Catherine of Genoa
– St. Catherine of Siena. The Dialogue*
= Eadmer. Vita Sancti Anselmi (Life of St. Anselm)*
– St. Bernard of Clairvaux. On Loving God*
– St. Thomas Aquinas. Summa Theologica, On Prayer and the Contemplative Life
– St. Hildegard of Bingen. Scivias, Liber Vitae Meritorum (Book of the Rewards of Life)
– Julian of Norwich. Showings.
– The fiction series Knightfall on History about the Templars teaches little tradition but may give some a feel for the age.